Submergible hull propulsion and control system



March 24, 1964 ALSAGER ETAL 3,125,975

SUBMERGIBLE HULL PROPULSION AND CONTROL SYSTEMS Filed April 25, 1962FIG. I.

INVENTORS L. E. ALSAGER R. A. BRAND United States Patent 3,125,975SUBMERGIBLE HULL PROPULSIGN AND CONTRGL SYSTEMS Leslie E. Alsager, FallsChurch, Va, and Robert A.

Brand, Bethesda, Md, assignors to the United States of America asrepresented by the Eecretary of the Navy Filed Apr. 25, 1962, Ser. No.190,183 5 Claims. (Cl. 114-16) (Granted under Title 35, US. Code (1952),see. 266) The invention described herein may be rnanufiactured and usedby or for the Government of the United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to improvements in submergible vessels; and, moreparticularly, relates to m improved deep submergence hull and propulsionsystem.

It has been found that prior art hulls and propulsion systems haveweaknesses at great depths, one of these weaknesses being the diificultyof sealing the propulsion means where it passes through the hull.Conventional high pressure rotating seals are rather inefficient onvessels capable of deep submergence. At great depths, controlled sealleakage for lubrication purposes cannot be carried out efiicientlywithout excess leakage. In addition not only do high pressure rotaryseal have a short operating life and high replacement cost resulting inlong operational down time, but they also become increasinglymechanically inefficient as their size becomes larger due to thenecessity of large shafits on large high speed submergible vessels.Types of seal arrangements have also been proposed wherein sea watercomes into intimate contact with rotating elements for purposes ofinternal and external pressure equalization. However, these systems arelimited to a short operating life due to the corrosive and erosiveeiieots of sea water on the various components. Moreover, all machineryexposed to sea water must be sealed, thus adding to the total number ofseals necessary and to the weight of sealing material.

Accordingly, it is among the objects of the present invention to providean improved hull and propulsion system for submergi-ble vessels; toprovide a deep submergence hull and propulsion system safely andetliciently operational not only at any depth, but particularly at greatdepths, says, sevenal thousand feet; to provide in a simple andeffective manner the substantial elimination of pressure dilieren-tialin a portion of a hull at any depth; and to provide a deeply submergiblehull and propulsion system which is safe, which requires a minimum ofmaintenance and expense, and which may be utilized by itself and easilyadapted for incorporation with existing vessels.

These and other objects, tteatures and advantages of the presentinvention will be better understood by referring to the drawings inwhich the same reference numerals represent like parts and in whichFIGS. 1 and 2 are illustrative diagrams of difierent embodiments of thepresent invention.

Referring to FIG. 1 the after end of a submergible vessel .11 is shownhaving substantially fixed pressure a chamber 13 formed by relativelystrong (e.g. thick) surrounding walls 15 for withstanding the highpressure differentials occurring at great depths in water. A variablepressure chamber 17 located aft of the thick-walled chamber 13 may beformed by relatively weak (e.g. thin) surrounding walls 19 capable ofwithstanding relatively low inward or outward diiierential pressure ascompared with the thick walls 15. The thin walls 19 may be integrallyjoined to the thick walls 15 at a station of the submarine 11 having alarge cross section so that the 3,125,975 Patented. Mar. 24, 1964,.

Walls 19 form a smooth aftward extension of the body of the submarine'11 to enhance smooth water flow.

The attermost end of the thin-walled variable pressure chamber 17 has anopening 21 into which is fitted a conventional bearing and seal 23supporting a propeller shaft 25 having a propeller 27. The bearing andseal 23 need withstand only relatively small or negligible pressuredifierentials.

The interior of the thin-walled variable pressure chamber 17 ispreferably filled as completely as possible with fluid means such as anessentially lubricative liquid which does not have corrosive and erosiveeffects on machinery. Any suitable oil may be used. Oils of the typeknown as MILT2 -T.E.P., 21101-1 and silicon oils have been found to besatisfactory.

As an alternative, the thin-walled chamber 17 may be filled partiallywith a suitable liquid and the remainder filled with a gas. However, inthis instance the ratio of the liquid to gas must be appropniate topermit sutiicient changes in pressure in .the chamber 17 tosubstantially match that of the surrounding sea Water at depths to whichthe chamber 17 may be lowered. Since the gas in the chamber 17 may wellbe at considerably higher than atmospheric pressure, it would in thisinstance be necessary to seal the chamber 17 against the escape of thegas.

An aperture 29 is located in the thin-walls 19 of the chamber 1'7 and iswatertightly surrounded by volumecha-nging means, for example, anexpandable and contractible hollow body such as a bellows or diaphragm31 mounted in any suitable watertight manner on the inside portion ofthe thin walls '19 with the interior of the diaphragm 3'1 communicatingwith the aperture 29. The diaphragm 31 need Withstand only thesepressure diflferentials withstandable by the thin walls 19. Thediaphragm 31 contracts and expands thus changing its volume and,consequently, the pressure in the chamber 17 according to the differencein pressure between the surrounding sea water and the interior of thechamber 17. In the situation where the chamber 17 is filled with acombination of gas and liquid, the limits of expansion and contractionof the diaphragm 31 will necessarily be greater than in the case whereonly a liquid is used to fill the chamber 17. essentially completely.

As shown in FIG. 1, power-plant means employing a motor 33 which may beof any suitable type is located inside the thick walled chamber 13 andis connected by suitable linkage to drive a reversible vaniable deliverypump 35. A conduit 37 watertigh-tly passing through the thick walls 15is connected to the pump 35 to deliver liquid from the thin walledchamber 17 acting as a reservoir to the pump 35. A pair of conduits 39water-tightly passing through the walls 15 feeds the output of the pump35 to a suitable hydraulic torque converter such as a hydraulic drivemotor 41 of any suitable construction. The hydraulic motor 41 in turndrive-s the shaft 25 either directly or through suitable reductiongearing. Obviously by reversing the direction of delivery of the pumpthe propeller rotation direction is controlled.

In the embodiment of the invention of PEG. 2, propulsion meanscomprising an electric drive system for providing higher shafthorsepower than that generally obtainable by a hydraulic drive system isshown. Any suitable source of electrical power such as a battery .43which may be of the type submergible in oil, or a incl cell or the like,is located in the thin-walled chamber 17. The battery source 43 isconnected via a lead 45 and lead a 49 to respective input terminals of asuitable power switch unit 5-1 also located in the chamber 17, Leads 53and 54 connect output terminals of the switch unit 51 to the terminalsor" an electric motor 4-7 driving the propeller. A pair of leads 55connect control terminals of 3 the high power switch unit 51 to a remotecontrol console 57 located in the thick-walled chamber 13.

The switch unit 51 may include a solenoid actuated relay for reversingthe polarity on the field or armature winding terminals of the motor 4 7to thereby reverse its direction of rotation and a potentiometeractuated by a servo motor or other suitable means for adjusting thecurrent in the motor windings. The control console 57 is provided withany suitable controls tor energizing the switch uni-t 51.

With the switch unit 51 located in the oil-filled thinwalled chamber 17as just described, insulation for the relatively high voltages in theswitch unit 51 is inherently provided. It is to be understood, however,that the switch unit 51 or the battery source 43, or both, may belocated in the thick-walled chamber 13 it desired. The motor 47 maydrive the propeller shaft 25 directly or through suitable reductiongearing.

According to the operating principles of the present invention, as thesubmergible vessel 11 descends, the diaphragm 31 expands in the chamber17 due to the sea water pressure applied thereto via the aperture 2 9'.The expanding diaphragms 31 reduces the volume of the oil or fluidscontained in the chamber 17, thereby increasing the outward pressure onthe walls 19 of the chamber 17. The diaphragm 31 will continue expandinguntil the interior pressure of the chamber 17 is at least approximatelyequal to the pres-sure of the surrounding sea water. How ever, there mayyet remain a slight differential in pressure on the walls 19 and on thediaphragm 3 1 because oti the structural resistance and inertia of thediaphragm 31. Accordingly, as a practical matter, it may be necessary tomake the thin walls 19 and diaphragm 3 1 of sufficient material strength(eg. thickness) to withstand such a resulting pressure differential.

Of course, when the submarine 11 is caused to ascend, the diaphragm 31contracts in the thin-walled chamber 17 proportionately to thedecreasing pressure or the sur rounding sea water, again resulting in avery small or negligible differential in pressure acting on the walls19.

It will thus be appreciated that with a small or negligible pressurediflerential acting on the thin-walled chamber 17, any rotary or othertypes of seals located in the thinawalls '19 need be made to withstandonly very small or negligible pressure differentials. Consequently, theleakage of such seals will be quite low. Moreover, it will beappreciated that the depths to which a submergible vessel having thehull and propulsion system according to the present invention maydescend are practically unlimited. It is necessary only that the limitof expansion of the diaphragm 31 be sufiicient to maintain the lowdifferential in pressure withstandable by the thin walls 19 and sealleakage limitations. In some cases it may be necessary to use more thanone diaphragm in the thinwalled chamber 17, and it is obvious that othertypes of expandable and contractable devices may be used in lieu of thediaphragm, such as bags, sliding joint couplings, piston and cylinderarrangements, bellows, etc.

It will be realized that not only does the system according to thepresent invention provide extended life over any other known systemwhich operates with sea water in contact with, surrounding, or internalto the rotating and fixed elements, but it also provides a minimum ofleakage problems and permits bidirectional propeller rotation. Moreover,the liquid in the chamber 17 serves to cool any machinery or mechanismswhich may be provided therein such as, in addition to those illustratedand discussed above, reversing thrust bearings, propeller drive shaftsupport bearings, auxiliary machinery, and the like.

In an emergency, fresh water may replace the oil in the variablepressure chamber 17 when there are no uninsulated electricallyconducting elements in the chamber 17, and in an extreme emergency, evensea water may be used for short periods, thus giving the system of thepresent invention a considerable degree of back-up safety.

It is to be understood that according to the invention the thin-walledchamber 17 may be used by itself without attachment to anything else incertain situations where it is unnecessary that personnel accompany thechamber 17 to depths to which it may be lowered. Where the chamber 17and appropriate equipment contained therein is used by itself, the thinwalls 19* thereof would be completely surrounding the liquid 2'18instead of there being a wall in common with the vessel to which thechamber 17 may be attached.

Obviously many modifications and variations of the present invention arepossible in the light of the above teachings. It is therefore to beunderstood that Within the scope of the appended claims the inventionmay be practiced otherwise than as specifically described.

What is claimed is:

1. A submergible vessel comprising:

(a) a substantially fixed pressure chamber having walls of sumcientstrength to withstand all differential pressures to which the chambermay be swbjected;

(11) a variable pressure chamber having walls capable of withstanding adifferential in pressure lower than those to which the vessel is to besubjected;

(c) said fixed and variable pressure chambers being connected to form aunitary body;

(at) powerplant means located in said fixed pressure chamber;

(e) propeller shaft means located in said variable pressure chamber andresponsive to said powerplant means for driving said vessel throughwater;

(f) a pool of liquid substantially entirely filling said variablepressure chamber;

(g) said variable pressure chamber having aperture means in the wallsthereof; and

(11) volume changing means watertightly surrounding said aperture anddisposed in the interior of said variable pressure chamber for varyingthe pressure in said variable pressure chamber in response to the seawater pressure acting through said aperture means on said volumechanging means.

2. The vessel as defined in claim 1 but tfurther characterized by atleast a portion of said powerplant means being located in said [fixedpressure chamber.

3. The vessel as defined in claim 1 but further characterized by controlmeans located in said fixed pressure chamber for controlling saidpowerplant means and said propeller shaft means.

4. A self-propelled submergible vessel comprising:

a substantially fixed pressure chamber having walls of sufficientstrength to withstand all difierential pressures to which the chambermay be subjected;

a variable pressure chamber located tandemly of said fixed pressurechamber and sharing a common Wall therewith;

said variable pressure chamber having walls capable of withstanding apressure differential lower than those to which the vessel may besubjected;

a pool of liquid substantially entirely filling said Variable pressurechamber;

said variable pressure chamber having aperture means in its Walls;

changeable volume hollow body means watertightly surrounding saidaperture means and disposed in the interior of said variable pressurechamber for varying the pressure in said variable pressure chamber inresponse to sea water pressure acting through said aperture means onsaid changable volume hollow body means;

a power-plant located in said fixed pressure chamber;

reversible pump means located in said fixed pressure chamber and coupledto said powerplant for being driven thereby;

a propeller shaft extending through the wall of said 5 variable pressurechamber and supported at its wall by bearing means;

a drive unit located in said variable pressure chamber and coupled tosaid propeller shaft for driving the shaft; and 5 fixed conduit meanspassing fiui'dtightly through said common vv all for coupling saidreversible pump to said drive unit.

5. A self-propelled vessel according to claim 4 but furthercharacterized by said reversible pump means having 1 a fixed reservoirconduit extending through the wall of said fixed pressure chamber andhaving its intake end located in said variable pressure chamber.

References Cited in the file of this patent UNITED STATES PATENTS DAlbaySept 27, Miller Oct. 25, Rondot June 27, Gory] et a1. Apr. 16,

FOREIGN PATENTS Great Britain Nov, 19, Great Britain Feb. 24, FranceApr. 10,

1. A SUBMERGIBLE VESSEL COMPRISING: (A) A SUBSTANTIALLY FIXED PRESSURECHAMBER HAVING WALLS OF SUFFICIENT STRENGTH TO WITHSTAND ALLDIFFERENTIAL PRESSURES TO WHICH THE CHAMBER MAY BE SUBJECTED; (B) AVARIABLE PRESSURE CHAMBER HAVING WALLS CAPABLE OF WITHSTANDING ADIFFERENTIAL IN PRESSURE LOWER THAN THOSE TO WHICH THE VESSEL IS TO BESUBJECTED; (C) SAID FIXED AND VARIABLE PRESSURE CHAMBERS BEING CONNECTEDTO FORM A UNITARY BODY; (D) POWERPLANT MEANS LOCATED IN SAID FIXEDPRESSURE CHAMBER; (E) PROPELLER SHAFT MEANS LOCATED IN SAID VARIABLEPRESSURE CHAMBER AND RESPONSIVE TO SAID POWERPLANT MEANS FOR DRIVINGSAID VESSEL THROUGH WATER; (F) A POOL OF LIQUID SUBSTANTIALLY ENTIRELYFILLING SAID VARIABLE PRESSURE CHAMBER; (G) SAID VARIABLE PRESSURECHAMBER HAVING APERTURE MEANS IN THE WALLS THEREOF; AND (H) VOLUMECHANGING MEANS WATERTIGHTLY SURROUNDING SAID APERTURE AND DISPOSED INTHE INTERIOR OF SAID VARIABLE PRESSURE CHAMBER FOR VARYING THE PRESSUREIN SAID VARIABLE PRESSURE CHAMBER IN RESPONSE TO THE SEA WATER PRESSUREACTING THROUGH SAID APERTURE MEANS ON SAID VOLUME CHANGING MEANS.